CN104807850A - Experimental device and method for measuring thermodynamic parameters of oil gas well shaft fluid and oil well pipe - Google Patents

Abstract

The invention discloses an experimental device and method for measuring the thermodynamic parameters of wellbore fluid and oil well pipes of oil and gas wells. The technical problem to be solved is to provide a device that can effectively measure the thermodynamic parameters of wellbore fluid and oil well pipe, and guide the design of high-temperature and high-yield oil and gas wells. The invention adopts coaxial three-layer pipes (oil pipe, inner layer casing and outer layer casing), the ratio of the length of the coaxial three-layer pipes to their radius is greater than 10, and the ends are sealed and connected by flanges. The simulated temperature (constant temperature, temperature 1) fluid continues to flow in the tubing under the set displacement, the inner casing is filled with the fluid to be tested, and the simulated temperature (constant temperature, temperature 2) fluid continues to flow in the outer casing under the set displacement flow. The invention can measure the thermodynamic parameters of the fluid and the oil well pipe, and can also directly measure the thermal expansion pressure generated by the temperature effect.

Description

An experimental device and method for measuring the thermodynamic parameters of oil and gas well wellbore fluid and oil well pipe

technical field

The present invention relates to an experimental device and method for researching and measuring thermodynamic parameters of wellbore fluid of oil and gas wells and oil well pipes (oil well pipes refer to: drill pipes, oil pipes and casings used in the oil and gas industry), in particular to a method for measuring the wellbore of oil and gas wells Experimental device and method for thermodynamic parameters of fluid and oil well pipe.

Background technique

During the production of high-temperature and high-yield oil and gas wells, the temperature of the wellbore increases greatly, and the annular pressure caused by thermal expansion has a very serious impact on the sealing of the casing and safe production. In the process of testing and production, the increase of annular pressure caused by a large increase in temperature will cause problems in the internal pressure/extrusion resistance of the inner and outer casings; at the same time, as the temperature increases, the axial pressure will increase, which will cause The casing bends and even tops the wellhead, even causing the oil and gas well to be scrapped. Therefore, it is particularly important to study the thermodynamic parameters of wellbore fluid and oil well tubing in oil and gas wells.

Contents of the invention

The technical problem to be solved by the present invention is to provide an experimental device and method for measuring the thermodynamic parameters of oil and gas well bore fluid and oil well pipe.

In order to solve the above technical problems, the main components of the experimental device for measuring the thermodynamic parameters of oil and gas well bore fluid and oil well pipe of the present invention are: main body, constant temperature fluid circulation system (heat source), constant temperature fluid circulation system (cold source), temperature measurement Pressure system, display and acquisition system, and temperature control system; the main part adopts coaxial three-layer pipe, which includes oil pipe, inner casing and outer casing in sequence. The ratio of the length of the coaxial three-layer pipe to its radius is greater than 10, and the end The parts are sealed and connected with flanges to form an absolutely sealed sleeve. The simulated temperature (constant temperature, temperature 1) fluid continuously flows in the oil pipe. The inner casing is filled with the fluid to be tested and a thermocouple is placed, and the outer casing continues to flow. Simulate temperature (constant temperature, temperature 2) fluid; constant temperature fluid circulation system includes agitator, water tank, refrigeration circuit, heating temperature control system, water pump, valve and water temperature display; through the temperature control system, the fluid in the oil pipe and the outer casing can be controlled The temperature is controlled in real time, and the temperature and pressure testing and collection are completed by the temperature measurement and pressure measurement system and the display and collection system, and are connected to the computer through the communication interface.

Further, the input port and the output port of the oil pipe are respectively connected to the constant temperature fluid circulation system (heat source) to form a loop, and the input port and the output port of the outer casing are respectively connected to the constant temperature fluid circulation system (cooling source) into a loop.

Furthermore, multiple sets of thermocouples are placed in the inner casing, each group of two thermocouples are respectively attached to the outer wall of the oil pipe and the inner wall of the inner casing, and the thermocouples are connected to the temperature and pressure measurement, data acquisition and temperature control modules. Thermocouples are also placed at the fluid input and output ports, and the thermocouples are K-type thermocouples.

Furthermore, a pressure sensor is placed on the top of the inner casing and connected to a temperature measurement and pressure measurement module to directly measure the thermal expansion pressure caused by the temperature effect.

Further, the bottom of the outer casing can be filled with solid cement to simulate the actual downhole cementing section.

Further, based on the above-mentioned experimental device, the present invention also provides an experimental method, said method comprising the following steps:

The first step, experiment preparation:

Measure the diameter, wall thickness and length of the three-layer pipe respectively, place 10 groups (2 in each group) of thermocouples, and check the distribution and working conditions of the thermocouples on the outer wall of the tubing and the inner wall of the inner casing to ensure that they are evenly distributed and normal. Work; measure the density of the fluid to be tested.

The second step is to measure the thermodynamic parameters of wellbore fluid and oil well pipe:

Firstly, the fluid to be tested is transported into the inner casing, and then the valves of each constant temperature fluid circulation system are respectively opened, so that the simulated temperature (constant temperature, temperature 1) fluid and the simulated temperature (constant temperature, temperature 2) fluid are under the set displacement. The circulation flows into the oil pipe and the outer casing, and the temperature is controlled within the set value range. When the fluid temperature gradually stabilizes and reaches thermal equilibrium, close the valves of each fluid circulation system, and collect and record when the oil pipe temperature drops to a certain temperature over time. The temperature and pressure to be measured, and the volume of the fluid in the oil pipe are measured, according to the thermal conductivity measurement formula of the steady state method:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; C\&rho;V\&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;L\&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}$

Calculate the thermal conductivity of the fluid to be measured, where C is the specific heat capacity of the fluid to be measured, ρ is the density of the fluid to be measured, V is the volume of the fluid in the tubing, L is the length of the tubing, ΔT ₁ is the temperature difference between the two ends of the tubing, ΔT ₂ is the difference between the average temperature of the fluid cross-section to be measured, r ₁ is the inner diameter of the tubing, and r ₂ is the inner diameter of the inner casing.

In the third step, repeat the second step, change the temperature condition, and measure the thermal conductivity of the fluid to be tested at multiple temperatures.

The fourth step is to keep the temperature and the type of fluid to be tested unchanged, use oil pipes and casings of different materials to conduct experiments, and calculate the thermal conductivity of different pipe materials.

The fifth step, the end of the experiment, record the experimental results. Pump the fluid out of the unit and clean the unit.

The advantages of the present invention are:

(1) The static experiment can only measure the thermal conductivity of the fluid under static conditions. The present invention uses the flow method to measure the thermal conductivity of the fluid, which can better simulate the on-site environment of oil well pipes. The device has high temperature resistance, high pressure resistance, simple structure, and is easy to use. Good disassembly and sealing effect.

(2) Through effective heat insulation measures, the heat loss of natural convection heat transfer and radiation heat loss are effectively reduced.

(3) The present invention can be heated by circulating fluid with constant temperature and stable flow rate, which is suitable for high temperature resistant fluid.

(4) The device is suitable for the research of thermodynamic parameters of wellbore fluid and oil well tubing in oil and gas wells. It can simply and effectively measure the thermal conductivity and thermal expansion pressure of wellbore fluid and oil well tubing during oil and gas migration, and the accuracy of the test is relatively high. high.

Description of drawings

Fig. 1 is a device diagram for measuring oil and gas well bore fluid and oil well pipe thermodynamic parameters provided by the present invention;

Fig. 2 is a schematic diagram of the main part of the test device in the present invention;

Fig. 3 is a schematic diagram of a constant temperature fluid circulation system;

The marks in the figure are: main part of test device 1, constant temperature fluid circulation system (heat source) 2, constant temperature fluid circulation system (cold source) 3, temperature measurement and pressure measurement 4, data acquisition 5, temperature control 6, insulating material 7, oil pipe 8 , inner casing 9, outer casing 10, flange 11, simulated temperature (constant temperature, temperature 1) fluid 12, fluid to be measured 13, thermocouple 14, simulated temperature (constant temperature, temperature 2) fluid 15, tubing fluid Input port 16, oil pipe fluid output port 17, outer casing fluid input port 18, outer casing fluid output port 19, solid cement 20, agitator 21, water tank 22, refrigeration circuit 23, heating temperature control system 24, water pump 25, valve 26, water temperature display 27.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Experimental device for measuring oil and gas wellbore fluid and oil well pipe thermodynamic parameters, including main part 1, constant temperature fluid circulation system (heat source) 2, constant temperature fluid circulation system (cold source) 3, temperature measurement and pressure measurement system 4 and display and acquisition system 5 It is composed of 6 temperature control systems. The main part 1 of the device is composed of coaxial three-layer pipes, including the oil pipe 8, the inner layer casing 9 and the outer layer casing 10 in turn, and the end is sealed with a flange 11 to form an absolutely sealed sleeve, which lasts in the oil pipe 8 A simulated temperature (constant temperature, temperature 1) fluid 12 is flowing, the inner casing 9 is filled with a fluid 13 to be measured and a thermocouple 14 is installed, and a simulated temperature (constant temperature, temperature 2) fluid 15 is continuously flowing in the outer casing 10, The bottom is insulated and sealed by insulating material 7 . The input port 16 and the output port 17 of the oil pipe are connected to the constant temperature fluid circulation system 2 to form a loop, and the input port 18 and the output port 19 of the outer casing are respectively connected to the constant temperature fluid circulation system 3 to form a loop; the two sets of constant temperature fluid circulation systems are composed of Stirrer 21, water tank 22, refrigeration circuit 23, heating and temperature control system 24, water pump 25, valve 26 and water temperature display 27; through the temperature control system 6, the temperature of the fluid in the pipe can be controlled in real time, and the temperature and pressure can be tested The temperature and pressure measurement 4 and the display and acquisition system 5 are used to complete the measurement and collection, and are connected to the computer through a communication interface.

The water pump 25, the heating and temperature control system 24 and the refrigeration circuit 23 can respectively change the flow rate and temperature of the fluid 12 in the tubing and the fluid 15 in the outer casing, thereby simulating the changes in various parameters of the actual downhole working environment, and exploring the effects of various factors on The degree of influence of wellbore fluid and oil well pipe thermal conductivity. In order to measure each parameter value, corresponding sensors can be set and connected to a display device to display the sensor signals for easy observation and recording. For example, a pressure sensor and a thermocouple 14 are connected to the display and acquisition system 5 to detect the pressure and temperature of the fluid in the pipe respectively.

The experimental method suitable for measuring the thermodynamic parameters of the wellbore fluid of the oil and gas well and the oil well pipe provided by the invention belongs to the steady state method. The steady-state method refers to the test after the temperature distribution on the test sample is stable, and the thermal conductivity is directly measured through the steady-state differential equation of heat conduction.

Because the heat generated in the oil pipe Q=CmΔT, that is, the heat generated by the oil pipe per unit time According to m=ρV, so the heat generated in the oil pipe The radial heat transfer generated by the fluid under the action of temperature difference is According to the law of energy conservation, the heat generated in the oil pipe is equal to the sum of the radial heat loss generated, Q ₁ =Q ₂ .

Then the thermal conductivity of the fluid to be measured in the inner casing is:

According to the above principles, the experimental steps of this method are as follows:

The first step, experiment preparation:

Measure the diameter, wall thickness and length of the three-layer pipe respectively, place 10 groups (2 in each group) of thermocouples, and check the distribution and working conditions of the thermocouples on the outer wall of the tubing and the inner wall of the inner casing to ensure that they are evenly distributed and normal. Work; measure the density of the fluid to be tested.

The second step is to measure the thermodynamic parameters of wellbore fluid and oil well pipe:

First, the fluid to be tested is transported into the inner casing, and the temperature and pressure are controlled within the range of simulated downhole production conditions, and then the valves of each constant temperature fluid circulation system are respectively opened to make the simulated temperature (constant temperature, temperature 1) fluid and the simulated temperature ( Constant temperature, temperature 2) The fluid circulates into the oil pipe and the outer casing under the set displacement. When the fluid temperature gradually stabilizes and reaches thermal equilibrium, close the valves of each fluid circulation system, and the oil pipe temperature decreases to a certain temperature with time. Collect and record the temperature and thermal expansion pressure values to be measured, and measure the volume of the fluid in the oil pipe, according to the thermal conductivity measurement formula of the steady state method:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; C\&rho;V\&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;L\&Delta;</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}$

Calculate the thermal conductivity of the fluid to be measured, where C is the specific heat capacity of the fluid to be measured, ρ is the density of the fluid to be measured, V is the volume of the fluid in the tubing, L is the length of the tubing, ΔT ₁ is the temperature difference between the two ends of the tubing, ΔT ₂ is the difference between the average temperature of the fluid cross-section to be measured, r ₁ is the inner diameter of the tubing, and r ₂ is the inner diameter of the inner casing.

In the third step, repeat the second step, change the temperature condition, and measure the thermal conductivity of the fluid to be tested at multiple temperatures.

The fourth step is to keep the temperature and completion fluid type constant, use tubing and casing of different materials to conduct experiments, and calculate the thermal conductivity of different tubing materials.

The fifth step, the end of the experiment, record the experimental results. Pump the fluid out of the unit and clean the unit.

Claims (7)

1. measure an experimental provision for Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter, it is characterized in that: comprise main part (1), the constant temperature fluid circulation system (thermal source) (2), the constant temperature fluid circulation system (low-temperature receiver) (3), thermometric pressure measuring system (4), display and acquisition system (5) and temperature control system (6), main part (1) adopts coaxial three layers of pipe, comprise oil pipe (8) successively, nexine sleeve pipe (9) and outer layer sleeve (10), coaxial three layers of tube length are all greater than 10 with the ratio of its radius, end flange (11) is tightly connected, form the sleeve of a positive confinement, analog temperature (the constant temperature that flows is continued in oil pipe (8), temperature 1) fluid (12), nexine sleeve pipe (9) interior filling is treated fluid measured (13) and is settled thermopair (14), analog temperature (the constant temperature that flows is continued in outer layer sleeve (10), temperature 2) fluid (15), the constant temperature fluid circulation system (2) comprises stirrer (21), tank (22), refrigerating circuit (23), heated for controlling temperature system (24), water pump (25), valve (26) and water temperature display (27), realize controlling in real time the temperature of oil pipe (8) and outer layer sleeve (10) inner fluid by temperature control system (6), the test of temperature, pressure and gathering is completed by thermometric pressure measuring system (4) and display and acquisition system (5), and is connected with computer by communication interface.

2. a kind of experimental provision measuring Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter as claimed in claim 1, it is characterized in that: connect into loop with the constant temperature fluid circulation system (2) respectively at the input port end (16) of oil pipe and delivery outlet end (17), be connected to loop with the constant temperature fluid circulation system (3) respectively at the input port end (18) of outer layer sleeve and delivery outlet end (19).

3. a kind of experimental provision measuring Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter as claimed in claim 1, it is characterized in that: settle in nexine sleeve pipe and organize thermopair more, often organize two thermopairs and be close to oil-pipe external wall and nexine internal surface of sleeve pipe respectively, thermopair controls (6) with thermometric pressure measurement (4), data acquisition (5) and temperature and is connected, at fluid input/output port end, place also settles thermopair respectively, and its thermopair adopts K type thermopair.

4. a kind of experimental provision measuring Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter as claimed in claim 1, is characterized in that: can simulate cementing concrete section under real well by the solid-state cement of filling (20) in the bottom of outer layer sleeve.

5. a kind of experimental provision measuring Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter as claimed in claim 3, it is characterized in that: at nexine cannula tip placement force sensor, be connected to thermometric manometric module (4), directly measure the thermal expansion stresses produced by temperature effect.

6. measure Oil/gas Well wellbore fluids for one kind, the experimental technique of oil well pipe thermodynamic parameter, it is characterized in that: adopt coaxial three layers of pipe (oil pipe, nexine sleeve pipe, outer layer sleeve), coaxial three layers of tube length are all greater than 10 with the ratio of its radius, bottom insulating material (7) sealing, to treat that fluid measured is delivered in nexine sleeve pipe, open constant temperature fluid circulation system valve respectively, when oil pipe and outer layer sleeve inner fluid temperature reach thermal equilibrium, measure interlayer temperature difference, calculate the heat that oil pipe provides, Fourier Heat Conduction philosophy is utilized to obtain flow thermal conductivity coefficient to be measured.

7. a kind of experimental technique measuring Oil/gas Well wellbore fluids, oil well pipe thermodynamic parameter as claimed in claim 6, is characterized in that: described method comprises the steps,

The first step, Preparatory work of experiment:

Measure the diameter of three layers of tubing, wall thickness and length respectively, place 10 groups of (often organizing 2) thermopairs, detect thermopair in oil-pipe external wall and nexine internal surface of sleeve pipe distribution situation and working condition, to guarantee that it is uniformly distributed and normally works; Measure the density treating fluid measured;

Second step, measure wellbore fluids, oil well pipe thermodynamic parameter:

First will treat that fluid measured is delivered in nexine sleeve pipe, then respectively by each constant temperature fluid circulation system valve open, make analog temperature (constant temperature, temperature 1) fluid and analog temperature (constant temperature, temperature 2) fluid circulation under the discharge capacity of setting flows in oil pipe and outer layer sleeve, and control temperature is in setting range, when fluid temperature (F.T.) gradually stable reach thermal equilibrium time, close each fluid circulating system valve, be reduced in time in oil pipe temperature in the process of uniform temperature and gather and record temperature and pressure value to be measured, and measure the volume of oil pipe inner fluid, according to steady state method thermal conductivity measurement formula:

$K=\frac{\mathrm{C\&rho;}{\mathrm{\&Delta;T}}_1\ln \frac{r_2}{r_1}}{2\mathrm{\&pi;L}{\mathrm{\&Delta;T}}_2\mathrm{\&Delta;t}}$

Calculate the coefficient of heat conductivity treating fluid measured, wherein C is the specific heat capacity treating fluid measured, and ρ is the density treating fluid measured, and V is the volume of oil pipe inner fluid, and L is the length of oil pipe, Δ T ₁for the temperature difference at oil pipe two ends, Δ T ₂for the difference of the medial temperature of fluid cross-section to be measured, r ₁for the internal diameter of oil pipe, r ₂for the internal diameter of nexine sleeve pipe;

3rd step, repeats second step, changes temperature conditions, measures the coefficient of heat conductivity treating fluid measured at multiple temperature;

4th step, keeps temperature, fluid type to be measured constant, and oil pipe, the sleeve pipe of use unlike material are tested, and calculate the coefficient of heat conductivity of different tubing;

5th step, experiment terminates, record experimental result.Fluid is pumped outside device, cleaning device.